1. Field of the Invention
The technical scope of the invention is that of safety and arming devices for projectiles, based on micro-electro-mechanical technology.
2. Description of the Related Art
The purpose of safety and arming devices (SAD) is to isolate the detonator and explosive load of a projectile and to enable these two components of the pyrotechnic train to communicate only (according to present-day standards such as STANAG 4157) when at least two distinct firing environment conditions appear.
Today research is being made into the production of these devices using MEMS (Micro Electro Mechanical Systems) technology which enables such devices to be miniaturized allowing them to be integrated into medium caliber projectiles, for example. The isolation between the detonator and the explosive load is more often than not made in the form of a plate, also called a screen, slider or barrier, which obstructs the slot by which these two components of the pyrotechnic train are made to communicate. Reference may be made to patent EP1780496 by which such a device is known.
These barriers able to stop a pyrotechnic effect are relatively thick with respect to the overall size of the MEMS safety and arming device. However, the scale at which the MEMS are produced means that the behavior of the mechanisms differs considerably from that of mechanisms made at the centimetric scale.
Thus, the phenomena of adhesion for thick parts becomes determining. At the MEMS scale, two plane surfaces brought into contact with one another adhere to one another relatively strongly thereby hindering relative movements in these planes. The problem arises in particular when the mobile element is in contact with the MEMS substrate.
The barrier is thus subjected to adhesion effects detrimental to the optimal, safe and reliable functioning of the SAD.